Answer to Question #102402 in Electric Circuits for james samuel damilola

Question

A moving coil instrument gives a full scale deflection (F.S.D) with a current of 30mA (0.030A) and a voltage of 90mv(0.090v). Calculate the value of a resistor to be connected in series with the instruments so that it can be used to read 0-100voltsr

Answer 1

Maximum deflection of the instrument occurs at 0.09 volts

we have to add a resistance that can measure 100 volts

resistance = voltage/ current =(100-0.09)/0.03 = 3330 $\Omega$